Heater



Jan. 15, 1924. 1,480,805

' F. v. HADLEY ET AL HEATER Filed July 20. 1921 2 Sheets-Sheet 1 f Tfake A35;

Jan. 15, 1924.

F. v. HADLEY ET AL HEATER 2 Sheets-Sheet 2 Filed July 20 one coo;

CARLETON, of Newton,

whereb erence to the drawings in which an Patented Jan. 1924.

UNITED STATES PATENT OFFICE.

FRED V. HADLEY, OF NEEDEAM,

HEATER.

Application filed July 20, 1921. Serial Ho. 486,210.

of Needham, in the county of Norfolk and State of Massachusetts, andRonmrr A.

in the county of Middlesex, in said State, have invented a new anduseful Improvement in Heaters, of which the following is aspecification.

Our invention relates to the heating of 1 the surface of drums, platesand the like such as the cylinders of a slasher or calenders or the likefor which it is particularly fitted, and we shall describe it inconnection with such a cylinder without, however, limiting 15 ourselvesto such use.

time for the cylinder to cool, as the drum of which it, is a part isusually so constructed that the heating fluid does not escape from thedrum, but is allowed to cool therein, which is a slow process. Moreover,

95 as steam cools it condenses and the drum is thus partially filledwith hot water, which still retains for a long time a high degree ofheat. Experience has shown that twelve hours and over may be necessaryto cool such a drum so that it may be handled for repairs or otherwise.

Our invention comprises im roved means for heating the desired suri ace,whether cylindrical or otherwise, by electricity, its temperature may.be quickly control ed, and also, whereby a higher degree of'temperaturemay be secured, if desired, than by the use of steam or hot air.

Our invention will be understood by refembodiment is shown applied to aslasher drum.

Fi re 1 is a section through the axis of the r um, the transformer beingshown in elevation, and

Fig. 2 is a section on line 2-2 of Fig. 1.

1 is a drum the cylindrical portion 21 of which is made of some metalhaving a comparatively high resistance. The ends of this drum may beclosed in by heads 2 insulated therefrom as shown or may be otherwisesupported as by spokes in a well known way on the shaft 3, 4 being smallreinforcing disks which serve as hubs by which the drum as a whole isattached to the shaft to turn therewith.

One end of the shaft 3 is provided with insulated collector rings 56, 57and 58 to which current is supplied from a source (not shown) by brushes6, 7 and 8.

9 is a transformer, the primary 101, 10 of which is connected b lead 16to the collector ring 58. The 0th mary coil is connected by wire 110with a safety device or circuit breaker 12 comprising a low fusiblemetal which is connected with a heat regulator 14 by the wire 13. Theheat regulator may be of any thermostatic character of which there aremany well known in the art. Its purpose is to break the circuit when theheat of the cylinder becomes too great. It is thus set to be operated bthe heat not of the cur rent but by the lieat of the cylinder so as toprevent the overheating of the product as below described. The circuitbreaker 12 is also of such a character as to break the circuit when thesurface of the cylinder temperature is too great, but the temperature atwhich the metal will fuse is higher than that at which the thermostatwill act and its purpose is to break the circuit only if the heatregulator for any reason does no act. The return circuit is by wire 15to ring 56 and brush 6.

The wire 11 connects brush 7 and ring 57 with the primary coil 10 sothat only part of the primary will be energized, the circuit bein alsocompleted through the wire 15 as before. Thus the heat of the cylindermay be regulated. If desired other divisions of the primary coil may besuitabl made.

The core of the transformer comprises preferably a laminated block 22 ofmagnetic metal having openings 23 forming a centre column 24 throughwhich passes the shaft 3 and around which is wound the coils 10, 101 ofthe primary.

er lead of the pri- The secondaries are shown at 17, the a transformerbeing of a step-down aha-race ducing the current that ter. lts circuitscomprise any desired number of low resistance radial bars 18, 181 whichare connected tothe bars 17 and are insulated from the heads 2 or otherdrum supports, but are electrically connected with the cylindricalportion 21 of the drum. These bars 18, 181 are connected to each otherby a number of cross bars 19, 191 so that current induced in thetransformer has the opportunity to reach the circumferential surface ofthe drum with the least possible resistance, and on reaching thecircumference 21 it passes through it and 181 and 191 completing thecircuit back to the transformer, and because of the comparatively higherresistance of the drum surface, that surface is heated a sufficientdegree to serve the purpose desired.

If too great heat is developed in the surface of the drum, the heatregulator will act to reduce the primary current, thus rewill flowthrough the secondary circuit, and the heating efiect. I

29 is a hand hole through which to get at the fuse 12 and heat regulator13, if desired.

l V e have described the device as made of high resistance metal. Thisterm, however, is comparative. it should be made of material of suchresistance as will readily heat to the required temperature under theaction of the current available and the construction of the transformer.And this may depend not only upon the kind of metal but upon itsthickness and general construction. lhe bars should be of very lowresistance both as to material and as to shape. Such matters beingwithin the knowledge of those skilled in the art, need not be furtherdescribed.

lt will be noted that in the application of this invention as abovedescribed the ma- ,v

terial to be treated is in directcontact with the electrically heatedsurface. By usinga' low tension current, the immediate source of whichmay be a transformer or some other source, a plate of comparatively highresistance in cylindrical or other suitable shape in a circuit ofcomparatively low resistance may be used as a support for the article toeco ing a step-down transformer the secondary of which comprisescomparatively low re sistance elements, and a dryer having a dryingportion composed of a comparatively high resistance metal, said lowresistance elements being connected in circuit with said drying portion,in combination with a primary circuit comprising a heat regulatorlocated to be heated by said dryer so that the temperature of said dryerwill control the current supplied thereto.

2. A dryer adapted to support the material to be dried and comprising ahollow drum having a drying and supporting surface of comparatively highresistance metal and a step-down transformer within said drum and thesecondary of which comprises comparatively low resistance elementsconnected in circuit with said dryer surface, in combination with aprimary circuit com prising heat-regulating means located to be directlyheated by said dryer and con-- structed whereby the temperature of saiddryer will control the current supplied thereto, said transformer beinglocated in said dryer and surrounded by an air space so that upon thebreaking of the primary circuit,'the dryer surface will promptly cool.

3. The machine above described comprising a drum having a surface ofcomparatively high resistance and a step-down transformer the secondaryof which comprises comparatively low resistance members connected to thehigh resistance portion of said drum whereby it will be in circuittherewith, 'a-source of current, a sectional primary and connectionsbetween said source and said primary whereby one or more sections ofsaid primary may be brought into circuit.

4. Armachine of the kind described comprising a body having a metallicsurface of high resistance, a source of current, and low resistanceconductors connecting said high .mesistance body with said source ofcurrent,

in combination with means located to be operated automatically by thetemperature of said metallic body whereby the amount of current passingto said body will be con tgroled, to control the temperature of said 0y. r v 5. In a heating mechanism, a source of electricity, a body ofhigh resistance having a surface adapted to support an article to beheated, whereby said article may be in di-' rect contact therewith, acurrent regulator receiving heat from'said body, and electricalconnections of low resistance between said body and said source.

6. In a heating mechanism, a source of low tension electricity, a bodyhaving a surface adapted to support in direct contact therewith anarticle to be heated, and electrical connections between said body andsaid source, the said body having a resistance high in comparison withthe resistance of said connections.

'2. Tie heating mechanism above described comprising a hollow drum theperipheral part of which consists of metal having a comparatively highresistance, a source of eiectricai current, a step-down transformerWithin said drum, and connections of comparatively low resistancebetween the secondary of said transformer and the high 10 resistanceportion of said drum.

FRED. V. HADLEY. ROBERT A. CARLETQN.

